1. Field of the Invention
The invention relates to an insert for bar peeling operations wherein the insert has a polygonal form in plan view as well as at least one primary cutting edge and one secondary cutting edge arranged at an obtuse angle thereto. The insert can also be reversible.
2. Discussion of Background Information
Semi-finished products, e.g., of stainless steel or of highly-alloyed materials, are generally produced by hot working the raw material. Before the semi-finished product is processed further, it can be necessary to machine the surface thereof. This machining is utilized in order to eliminate deformation troughs and/or oxide films or scale layers and/or defects therefrom. A dimensional accuracy of the semi-finished product that (may be desired) is also achieved in this manner.
A semi-finished product having a round cross section can be machined by cylindrical grinding, turning or bar peeling. Bar peeling of round bars is mostly utilized with larger batch sizes for economic reasons.
In principle, a device for bar peeling operations utilizes a rotating tool called a revolving head or peeling head with at least three cutting knives directed inwards. A knife trajectory circle of the tool has a smaller diameter than the round bar to be machined. The round bar is inserted into the rotating tool, and chips are removed by means of the knives while the round bar passes through the device. In this manner, round bars or rods can be sequentially manufactured with a machined surface in large production batches very economically.
In modern bar peeling devices so-called cassettes, which usually have inserts made of hard metal, are inserted and attached in the peeling head. The respective shape of the insert or peeling insert thereby depends on the tool system of the peeling machine, but in any case, the trajectory circle of the cutting edge therein forms a truncated cone on the feed side followed by a cylindrical section in the discharge direction. Accordingly, in plan view, peeling inserts have a polygonal shape with a primary cutting edge for the frusto-conical trajectory circle and, at an obtuse angle of approx. 155° thereto, a secondary cutting edge or smoothing cutting edge. The trajectory circle of runs essentially parallel to the rotational axis or with the same spacing thereto. The smoothing cutting edge also acts in a supporting manner for the machined bar, and guides it centrally in the peeling head.
In a coarse peeling operation, in particular with bar stock of stainless steels, highly nickeliferous alloys, and tough materials, tool chatter can increasingly occur with the use of known insert shapes. As a result, so-called chatter marks form on the machined surface. The electric power consumption of the peeling machine is also thereby increased and the service life of the peeling inserts seems reduced.